DETAILED SYLLABUS
HL IB Biology Year Two, 2015-16
4.1Essential idea: The continued survival of living organisms including humans depends on sustainable communities.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / Guidance4.1.U1 / Species are groups of organisms that can potentially interbreed to produce fertile offspring.
4.1.U2 / Members of a species may be reproductively isolated in separate populations.
4.1.U3 / Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods).
4.1.U4 / Consumers are heterotrophs that feed on living organisms by ingestion.
4.1.U5 / Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.
4.1.U6 / Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion.
4.1.U7 / A community is formed by populations of different species living together and interacting with each other.
4.1.U8 / A community forms an ecosystem by its interactions with the abiotic environment.
4.1.U9 / Autotrophs obtain inorganic nutrients from the abiotic environment.
4.1.U10 / The supply of inorganic nutrients is maintained by nutrient cycling.
4.1.U11 / Ecosystems have the potential to be sustainable over long periods of time.
4.1.S1 / Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition.
4.1.S2 / Setting up sealed mesocosms to try to establish sustainability. (Practical 5) / Mesocosms can be set up in open tanks, but sealed glass vessels are preferable because entry and exit of matter can be prevented but light can enter and heat can leave. Aquatic systems are likely to be more successful than terrestrial ones.
4.1.S3 / Testing for association between two species using the chi-squared test with data obtained by quadrat sampling. / To obtain data for the chi-squared test, an ecosystem should be chosen in which one or more factors affecting the distribution of the chosen species varies. Sampling should be based on random numbers. In each quadrat the presence or absence of the chosen species should be recorded.
4.1.S4 / Recognizing and interpreting statistical significance.
4.2Essential idea: Ecosystems require a continuous supply of energy to fuel life processes and to replace energy lost as heat.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / Guidance4.2.U1 / Most ecosystems rely on a supply of energy from sunlight.
4.2.U2 / Light energy is converted to chemical energy in carbon compounds by photosynthesis.
4.2.U3 / Chemical energy in carbon compounds flows through food chains by means of feeding. / Pyramids of number and biomass are not required. Students should be clear that biomass in terrestrial ecosystems diminishes with energy along food chains due to loss of carbon dioxide, water and other waste products, such as urea.]
4.2.U4 / Energy released from carbon compounds by respiration is used in living organisms and converted to heat.
4.2.U5 / Living organisms cannot convert heat to other forms of energy.
4.2.U6 / Heat is lost from ecosystems.
4.2.U7 / Energy losses between trophic levels restrict the length of food chains and the biomass of higher trophic levels. / The distinction between energy flow in ecosystems and cycling of inorganic nutrients should be stressed. Students should understand that there is a continuous but variable supply of energy in the form of sunlight but that the supply of nutrients in an ecosystem is finite and limited.
4.2.S1 / Quantitative representations of energy flow using pyramids of energy. / Pyramids of energy should be drawn to scale and should be stepped, not triangular. The terms producer, first consumer and second consumer and so on should be used, rather than first trophic level, second trophic level and so on.
4.3Essential idea: Continued availability of carbon in ecosystems depends on carbon cycling.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / Guidance4.3.U1 / Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds.
4.3.U2 / In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen carbonate ions.
4.3.U3 / Carbon dioxide diffuses from the atmosphere or water into autotrophs.
4.3.U4 / Carbon dioxide is produced by respiration and diffuses out of organisms into water or the atmosphere.
4.3.U5 / Methane is produced from organic matter in anaerobic conditions by methanogenicarchaeans and some diffuses into the atmosphere or accumulates in the ground.
4.3.U6 / Methane is oxidized to carbon dioxide and water in the atmosphere.
4.3.U7 / Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils.
4.3.U8 / Partially decomposed organic matter from past geological eras was converted either into coal or into oil and gas that accumulate in porous rocks.
4.3.U9 / Carbon dioxide is produced by the combustion of biomass and fossilized organic matter.
4.3.U10 / Animals such as reef-building corals and mollusca have hard parts that are composed of calcium carbonate and can become fossilized in limestone.
4.3.A1 / Estimation of carbon fluxes due to processes in the carbon cycle. / Carbon fluxes should be measured in gigatonnes.
4.3.A2 / Analysis of data from air monitoring stations to explain annual fluctuations.
4.3.S1 / Construct a diagram of the carbon cycle.
4.4Essential idea: Concentrations of gases in the atmosphere affect climates experienced at the Earth’s surface.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / Guidance4.4.U1 / Carbon dioxide and water vapour are the most significant greenhouse gases.
4.4.U2 / Other gases including methane and nitrogen oxides have less impact. / The harmful consequences of ozone depletion do not need to be discussed and it should be made clear that ozone depletion is not the cause of the enhanced greenhouse effect.
4.4.U3 / The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere. / Carbon dioxide, methane and water vapour should be included in discussions.
4.4.U4 / The warmed Earth emits longer wavelength radiation (heat).
4.4.U5 / Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere.
4.4.U6 / Global temperatures and climate patterns are influenced by concentrations of greenhouse gases.
4.4.U7 / There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures.
4.4.U8 / Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.
4.4.A1 / Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.
4.4.A2 / Correlations between global temperatures and carbon dioxide concentrations on Earth.
4.4.A3 / Evaluating claims that human activities are not causing climate change.
3.5Essential idea: Biologists have developed techniques for artificial manipulation of DNA, cells and organisms.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / Guidance3.5.U1 / Gel electrophoresis is used to separate proteins or fragments of DNA according to size.
3.5.U2 / PCR can be used to amplify small amounts of DNA.
3.5.U3 / DNA profiling involves comparison of DNA.
3.5.U4 / Genetic modification is carried out by gene transfer between species.
3.5.U5 / Clones are groups of genetically identical organisms, derived from a single original parent cell.
3.5.U6 / Many plant species and some animal species have natural methods of cloning.
3.5.U7 / Animals can be cloned at the embryo stage by breaking up the embryo into more than one group of cells.
3.5.U8 / Methods have been developed for cloning adult animals using differentiated cells.
3.5.A1 / Use of DNA profiling in paternity and forensic investigations.
3.5.A2 / Gene transfer to bacteria using plasmids makes use of restriction endonucleases and DNA ligase.
3.5.A3 / Assessment of the potential risks and benefits associated with genetic modification of crops.
3.5.A4 / Production of cloned embryos produced by somatic-cell nuclear transfer. / Dolly can be used as an example of somatic-cell transfer.
3.5.S1 / Design of an experiment to assess one factor affecting the rooting of stem-cuttings. [A plant species should be chosen for rooting experiments that forms roots readily in water or a solid medium.]
3.5.S2 / Analysis of examples of DNA profiles. / Students should be able to deduce whether or not a man could be the father of a child from the pattern of bands on a DNA profile.
3.5.S3 / Analysis of data on risks to monarch butterflies of Bt crops.
B.1 Essential idea:Microorganisms can be used and modified to perform industrial processes.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / GuidanceB.1.U1 / Microorganisms are metabolically diverse.
B.1.U2 / Microorganisms are used in industry because they are small and have a fast growth rate.
B.1.U3 / Pathway engineering optimizes genetic and regulatory processes within microorganisms.
B.1.U4 / Pathway engineering is used industrially to produce metabolites of interest.
B.1.U5 / Fermenters allow large-scale production of metabolites by microorganisms.
B.1.U6 / Fermentation is carried out by batch or continuous culture.
B.1.U7 / Microorganisms in fermenters become limited by their own waste products.
B.1.U8 / Probes are used to monitor conditions within fermenters.
B.1.U9 / Conditions are maintained at optimal levels for the growth of the microorganisms being cultured.
B.1.A1 / Deep-tank batch fermentation in the mass production of penicillin.
B.1.A2 / Production of citric acid in a continuous fermenter by Aspergillusnigerand its use as a preservative and flavouring.
B.1.A3 / Biogas is produced by bacteria and archaeans from organic matter in fermenters.
B.1.S1 / Gram staining of Gram-positive and Gram-negative bacteria.
B.1.S2 / Experiments showing zone of inhibition of bacterial growth by bactericides in sterile bacterial cultures.
B.1.S3 / Production of biogas in a small-scale fermenter.
B.2 Essential idea:Crops can be modified to increase yields and to obtain novel products.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / GuidanceB.2.U1 / Transgenic organisms produce proteins that were not previously part of their species’ proteome.
B.2.U2 / Genetic modification can be used to overcome environmental resistance to increase crop yields.
B.2.U3 / Genetically modified crop plants can be used to produce novel products
B.2.U4 / Bioinformatics plays a role in identifying target genes.
B.2.U5 / The target gene is linked to other sequences that control its expression.
B.2.U6 / An open reading frame is a significant length of DNA from a start codon to a stop codon. / A significant length of DNA for an open reading frame contains sufficient nucleotides to code for a polypeptide chain.
B.2.U7 / Marker genes are used to indicate successful uptake.
B.2.U8 / Recombinant DNA must be inserted into the plant cell and taken up by its chromosome or chloroplast DNA.
B.2.U9 / Recombinant DNA can be introduced into whole plants, leaf discs or protoplasts.
B.2.U10 / Recombinant DNA can be introduced by direct physical and chemical methods or indirectly by vectors. / Limit the physical methods of introducing genes into plants to electroporation, microinjection and biolistics (gunshot). Limit the chemical methods of introducing genes into plants to calcium chloride and liposomes.
B.2.A1 / Use of tumour-inducing (Ti) plasmid of Agrobacterium tumefaciensto introduce glyphosate resistance into soybean crops. / Limit vectors to Agrobacterium tumefaciensand tobacco mosaic virus.
B.2.A2 / Genetic modification of tobacco mosaic virus to allow bulk production of Hepatitis B vaccine in tobacco plants.
B.2.A3 / Production of Amflora potato (Solanumtuberosum) for paper and adhesive industries.
B.2.S1 / Evaluation of data on the environmental impact of glyphosate-tolerant soybeans.
B.2.S2 / Identification of an open reading frame (ORF).
B.3 Essential idea:Biotechnology can be used in the prevention and mitigation of contamination from industrial, agricultural and municipal wastes.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / GuidanceB.3.U1 / Responses to pollution incidents can involve bioremediation combined with physical and chemical procedures.
B.3.U2 / Microorganisms are used in bioremediation.
B.3.U3 / Some pollutants are metabolized by microorganisms.
B.3.U4 / Cooperative aggregates of microorganisms can form biofilms. / Examples of environmental problems caused by biofilms could include clogging and corrosion of pipes, transfer of microorganisms in ballast water or contamination of surfaces in food production.
B.3.U5 / Biofilms possess emergent properties.
B.3.U6 / Microorganisms growing in a biofilm are highly resistant to antimicrobial agents.
B.3.U7 / Microorganisms in biofilms cooperate through quorum sensing.
B.3.U8 / Bacteriophages are used in the disinfection of water systems.
B.3.A1 / Degradation of benzene by halophilic bacteria such as Marinobacter.
B.3.A2 / Degradation of oil by Pseudomonas.
B.3.A3 / Conversion by Pseudomonas of methyl mercury into elemental mercury.
B.3.A4 / Use of biofilms in trickle filter beds for sewage treatment.
B.3.S1 / Evaluation of data or media reports on environmental problems caused by biofilms.
B.4 Essential idea:Biotechnology can be used in the diagnosis and treatment of disease.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / GuidanceB.4.U1 / Infection by a pathogen can be detected by the presence of its genetic material or by its antigens.
B.4.U2 / Predisposition to a genetic disease can be detected through the presence of markers.
B.4.U3 / DNA microarrays can be used to test for genetic predisposition or to diagnose the disease.
B.4.U4 / Metabolites that indicate disease can be detected in blood and urine.
B.4.U5 / Tracking experiments are used to gain information about the localization and interaction of a desired protein.
B.4.U6 / Biopharming uses genetically modified animals and plants to produce proteins for therapeutic use.
B.4.U7 / Viral vectors can be used in gene therapy.
B.4.A1 / Use of PCR to detect different strains of influenza virus.
B.4.A2 / Tracking tumour cells using transferin linked to luminescent probes.
B.4.A3 / Biopharming of antithrombin.
B.4.A4 / Use of viral vectors in the treatment of Severe Combined Immunodeficiency (SCID).
B.4.S1 / Analysis of a simple microarray.
B.4.S2 / Interpretation of the results of an ELISA diagnostic test.
B.5 Essential idea:Bioinformatics is the use of computers to analyze sequence data in biological research.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / GuidanceB.5.U1 / Databases allow scientists easy access to information.
B.5.U2 / The body of data stored in databases is increasing exponentially.
B.5.U3 / BLAST searches can identify similar sequences in different organisms.
B.5.U4 / Gene function can be studied using model organisms with similar sequences.
B.5.U5 / Sequence alignment software allows comparison of sequences from different organisms.
B.5.U6 / BLASTn allows nucleotide sequence alignment while BLASTp allows protein alignment.
B.5.U7 / Databases can be searched to compare newly identified sequences with sequences of known function in other organisms.
B.5.U8 / Multiple sequence alignment is used in the study of phylogenetics.
B.5.U9 / EST is an expressed sequence tag that can be used to identify potential genes.
B.5.A1 / Use of knockout technology in mice to determine gene function.
B.5.A2 / Discovery of genes by EST data mining.
B.5.S1 / Explore chromosome 21 in databases (for example in Ensembl).
B.5.S2 / Use of software to align two proteins.
B.5.S3 / Use of software to construct simple cladograms and phylograms of related organisms using DNA sequences.
6.1Essential idea: The structure of the wall of the small intestine allows it to move, digest and absorb food.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / Guidance6.1.U1 / The contraction of circular and longitudinal muscle of the small intestine mixes the food with enzymes and moves it along the gut.
6.1.U2 / The pancreas secretes enzymes into the lumen of the small intestine. / Students should know that amylase, lipase and an endopeptidase are secreted by the pancreas. The name trypsin and the method used to activate it are not required.
6.1.U3 / Enzymes digest most macromolecules in food into monomers in the small intestine. / Students should know that starch, glycogen, lipids and nucleic acids are digested into monomers and that cellulose remains undigested.]
6.1.U4 / Villi increase the surface area of epithelium over which absorption is carried out.
6.1.U5 / Villi absorb monomers formed by digestion as well as mineral ions and vitamins.
6.1.U6 / Different methods of membrane transport are required to absorb different nutrients.
6.1.A1 / Processes occurring in the small intestine that result in the digestion of starch and transport of the products of digestion to the liver.
6.1.A2 / Use of dialysis tubing to model absorption of digested food in the intestine.
6.1.S1 / Production of an annotated diagram of the digestive system.
6.1.S2 / Identification of tissue layers in transverse sections of the small intestine viewed with a microscope or in a micrograph. / Tissue layers should include longitudinal and circular muscles, mucosa and epithelium.
6.2Essential idea: The blood system continuously transports substances to cells and simultaneously collects waste products.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / Guidance6.2.U1 / Arteries convey blood at high pressure from the ventricles to the tissues of the body.
6.2.U2 / Arteries have muscle cells and elastic fibres in their walls.
6.2.U3 / The muscle and elastic fibres assist in maintaining blood pressure between pump cycles.
6.2.U4 / Blood flows through tissues in capillaries. Capillaries have permeable walls that allow exchange of materials between cells in the tissue and the blood in the capillary.
6.2.U5 / Veins collect blood at low pressure from the tissues of the body and return it to the atria of the heart.
6.2.U6 / Valves in veins and the heart ensure circulation of blood by preventing backflow.
6.2.U7 / There is a separate circulation for the lungs.
6.2.U8 / The heart beat is initiated by a group of specialized muscle cells in the right atrium called the sinoatrial node.
6.2.U9 / The sinoatrial node acts as a pacemaker.
6.2.U10 / The sinoatrial node sends out an electrical signal that stimulates contraction as it is propagated through the walls of the atria and then the walls of the ventricles.
6.2.U11 / The heart rate can be increased or decreased by impulses brought to the heart through two nerves from the medulla of the brain.
6.2.U12 / Epinephrine increases the heart rate to prepare for vigorous physical activity.
6.2.A1 / William Harvey’s discovery of the circulation of the blood with the heart acting as the pump.
6.2.A2 / Pressure changes in the left atrium, left ventricle and aorta during the cardiac cycle.
6.2.A3 / Causes and consequences of occlusion of the coronary arteries.
6.2.S1 / Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.
6.2.S2 / Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts or in diagrams of heart structure.
6.3Essential idea: The human body has structures and processes that resist the continuous threat of invasion by pathogens.
Understandings, Applications and Skills (This is what you maybe assessed on)
Statement / Guidance6.3.U1 / The skin and mucous membranes form a primary defence against pathogens that cause infectious disease. / Diagrams of skin are not required.
6.3.U2 / Cuts in the skin are sealed by blood clotting.
6.3.U3 / Clotting factors are released from platelets.
6.3.U4 / The cascade results in the rapid conversion of fibrinogen to fibrin by thrombin.
6.3.U5 / Ingestion of pathogens by phagocytic white blood cells gives non-specific immunity to diseases. / Subgroups of phagocyte are not required
6.3.U6 / Production of antibodies by lymphocytes in response to particular pathogens gives specific immunity. / Subgroups of lymphocyte are not required but students should be aware that some lymphocytes act as memory cells and can quickly reproduce to form a clone of plasma cells if a pathogen carrying a specific antigen is re-encountered.
6.3.U7 / Antibiotics block processes that occur in prokaryotic cells but not in eukaryotic cells.
6.3.U8 / Viruses lack a metabolism and cannot therefore be treated with antibiotics. Some strains of bacteria have evolved with genes that confer resistance to antibiotics and some strains of bacteria have multiple resistance.
6.3.A1 / Causes and consequences of blood clot formation in coronary arteries.
6.3.A2 / Florey and Chain’s experiments to test penicillin on bacterial infections in mice.
6.3.A3 / Effects of HIV on the immune system and methods of transmission. / The effects of HIV on the immune system should be limited to a reduction in the number of active lymphocytes and a loss of the ability to produce antibodies, leading to the development of AIDS.
6.4Essential idea: The lungs are actively ventilated to ensure that gas exchange can occur passively.